1. Field of the Invention
The present invention relates to power switch technology and more particularly, to a safety lock mechanism for use in a trigger switch incorporated handle of a miter saw.
2. Description of the Related Art
A conventional miter saw (Taiwan Patent Publication No. 201325776) is known comprising: a base, a worktable rotatable relative to the base, a saw unit connected to one side of the worktable, and a positioning unit. The saw unit includes a saw arm pivotally connected to the worktable, a saw blade mounted at the saw arm, a motor mounted at the saw arm and adapted for rotating the saw blade, and an operating handle connected to the motor.
For the sake of safety and ease of operation, certain miter saws have a trigger mounted at the operating handle for controlling the power switch (see Taiwan Patent Publication No. 535674). When going to perform a cutting operation, the user can press the trigger at the operating handle to switch on the power supply of the motor, thereby starting the motor to rotate the saw blade. At this time, the user can move the saw blade downward toward the worktable to cut the workpiece.
These miter saws do not have any safety designs to prevent the trigger from being triggered accidentally. A user who is not very familiar with the operation mode can press the trigger accidentally, causing great danger by starting the rotation of the saw blade and cutting action.
In order to avoid the risk of the aforesaid danger, some other designs provide a power switch at the operating handle beyond the finger grip area for switching on the motor. However, the mounting position of the power switch is not conducive to a left-handed user. An improvement in this regard is desired.